Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932170Ab2HHGNq (ORCPT ); Wed, 8 Aug 2012 02:13:46 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:54496 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756920Ab2HHGNo (ORCPT ); Wed, 8 Aug 2012 02:13:44 -0400 Message-ID: <50220382.4010405@linux.vnet.ibm.com> Date: Wed, 08 Aug 2012 11:43:22 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 MIME-Version: 1.0 To: Kumar Gala CC: rjw@sisk.pl, Zhao Chenhui , "linuxppc-dev@lists.ozlabs.org list" , "linux-kernel@vger.kernel.org list" , Li Yang Subject: Re: [PATCH 3/4] cpu: export cpu hotplug disable/enable functions as global functions References: <1344329006-10645-1-git-send-email-chenhui.zhao@freescale.com> <1344329006-10645-3-git-send-email-chenhui.zhao@freescale.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 12080806-9264-0000-0000-000002153B4D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2104 Lines: 63 On 08/07/2012 11:21 PM, Kumar Gala wrote: > > On Aug 7, 2012, at 3:43 AM, Zhao Chenhui wrote: > >> The cpufreq driver of mpc85xx will disable/enable cpu hotplug temporarily. >> Therefore, the related functions should be exported. >> >> Signed-off-by: Zhao Chenhui >> --- >> include/linux/cpu.h | 4 ++++ >> 1 files changed, 4 insertions(+), 0 deletions(-) > > Rafael, Srivatsa, > > Wanted to get your ack on export these functions for direct calling by arch code. > Why not just use get_online_cpus()/put_online_cpus()? In the case of suspend/resume/hibernation, we had introduced these CPU hotplug disable functions because we would end up doing CPU hotplug ourselves, further down the path. So if we did a get_online_cpus(), we would end up deadlocking ourselves. Whereas, the patch 4/4 looks like a straightforward case of wanting to simply disable CPU hotplug.. I don't see where you are doing CPU hotplug yourself in the path. So IMO, just get/put_online_cpus() should do. Regards, Srivatsa S. Bhat > >> >> diff --git a/include/linux/cpu.h b/include/linux/cpu.h >> index ce7a074..df8f73d 100644 >> --- a/include/linux/cpu.h >> +++ b/include/linux/cpu.h >> @@ -146,6 +146,8 @@ void notify_cpu_starting(unsigned int cpu); >> extern void cpu_maps_update_begin(void); >> extern void cpu_maps_update_done(void); >> >> +extern void cpu_hotplug_disable_before_freeze(void); >> +extern void cpu_hotplug_enable_after_thaw(void); >> #else /* CONFIG_SMP */ >> >> #define cpu_notifier(fn, pri) do { (void)(fn); } while (0) >> @@ -167,6 +169,8 @@ static inline void cpu_maps_update_done(void) >> { >> } >> >> +static inline void cpu_hotplug_disable_before_freeze(void) {} >> +static inline void cpu_hotplug_enable_after_thaw(void) {} >> #endif /* CONFIG_SMP */ >> extern struct bus_type cpu_subsys; >> >> -- >> 1.6.4.1 >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/